Definition from Wiktionary, the free dictionary
- IPA: /ˈɪndɪsiːz/
- Plural form of index. (when used in the sense of a key to locate an element in a list, vector or matrix in computing or mathematics)
- The subscript numbers after each element are the indices of that element.
- A common convention in computing is to have indices beginning at zero, whereas in mathematics indices usually begin at one.
- 1972: American Society for Metals, Materials Science and Engineering, volumes 9–10,
- To locate any term, and to facilitate use of the dictionary by a national of any of the three languages, alphabetical indices are appended in English, French and German.
- 1976: Sidney Heath, The Romance of Symbolism and Its Relation to Church Ornament and Architecture, ISBN 0810343029, 9780810343023)
(Gale Research Co.;
- Perhaps the feature which most contributes to making this a valuable reference book is the appendices and indices which are an integral part of the guide.
- 1989: TAPPI Journal, volume 72,
(Technical Association of the Pulp and Paper Industry)
- Alphabetical indices of the terms in the other languages are given at the end of the book.
- 1999: Institute of Oriental Studies of the Saint-Petersburg Branch of the Russian Academy of Sciences, Manuscripta Orientalia: International Journal for Oriental Manuscript Research, volume 5,
- The dictionary’s four indices are helpful when searching terms. These are: Hanyu Pinyin System Index; Four-Corner System Index; Radical Index; and Japanese Reading System Index.
- 2000: Russian Language Journal, volume 54, issues 177–179,
(Michigan State University, Department of German & Russian)
- Its word indices makes[sic] finding individual words easy.
Usage notes 
- Both plurals are in common use. The OED claims that when referring to a directory listing, the plural indexes should be used.
- IPA: /ɛ̃.dis/
- Plural form of indice
Etymology 1 
Form of the verb indicō (“[I] indicate, point out”).
- second-person singular present active subjunctive of indicō
- "may you indicate, may you point out"
- "may you mention, may you give a hint of"
- "may you value, may you put a price on"
- "may you reveal, may you betray"
- "may you accuse"
- (law) "may you carry on a judicial process to conviction"
Etymology 2 
Form of the verb indīcō (“[I] proclaim, announce”).
- second-person singular future active indicative of indīcō
- "you will proclaim, you will announce"
- "you will fix (a destination)"
- (often with dative) "you will impose, you will afflict"
indices (infinitive indizar)